The objectives of the project are the conception, synthesis, and development of improved materials for use in preventive and restorative dentistry. The adhesion-promoting potentials of the following will be evaluated: (a) physiological solutions that can rapidly dissolve the "smeared" (disturbed) surface layer of dentin, (b) isotonic mordent (metallic salt) solutions to improve the cationic bonding sites, and (c) formulations of polyfunctional surface-active comonomers. The ingredients used in formulating composite materials will be evaluated for pulp irritation potential in primates. The objective is to determine the cause of pulp irritation under composite restorations that now occurs when calcium hydroxide liner materials are not used. Further assistance will be given to manufacturers to make available composites in which the reinforcing filler is comprised of "semiporous" glass filler particles. These strontium aluminoboro silicate glasses are heat treated to induce submicroscopic phase separations that lead to interpenetrating networks which form labyrinths of two vitreous structures. Methods for etching the surfaces to form superficial porosity and of treating these increased surface areas with a silane coupling agent will be optimized.